Use Debian stretch image

Signed-off-by: Dan Yeaw <dan@yeaw.me>

.circleci/config.yml

@@ -6,18 +6,20 @@ version: 2
 jobs:
   build:
     docker:
-      - image: circleci/python:3.7.2
+      - image: circleci/python:3.7.2-stretch
     working_directory: ~/repo
 
     steps:
       - checkout
       - run:
-          name: update packages
-          command: sudo apt update -q
+          name: pre-install
+          command: |
+            mkdir -p ~/.local/share
+            sudo apt update -q
       - run:
           name: install packages
           command: >
-            sudo apt install --no-install-recommends -y xvfb python3-dev python3-gi
+            sudo apt install --no-install-recommends -y python3-dev python3-gi
             python3-gi-cairo gir1.2-gtk-3.0 libgirepository1.0-dev libcairo2-dev
       - restore_cache:
           keys: